JPH03154356A - Tape carrier for mounting integrated circuit - Google Patents

Abstract

PURPOSE:To improve fitting of an insertion pin so as to prevent damage of sprocket holes by providing sprocket holes having different sizes on the surface and in the rear of a tape. CONSTITUTION:After sprocket holes 1b and device holes 2 of one side (the rear) are exposed and developed, about 1/2 of the tape thickness is etched. Next, the etched part is masked, while sprocket holes 1a, device holes 2 and lead frames 3 are similarly formed on the opposite face (the surface) of the tape, and the sprocket holes 1a and the sprocket holes 1b can be passed through. The sprocket holes 1b to be formed in the rear are to be formed to the measurements including the maximum amount of positional deviation of photomask at the time of exposure. Thereby, an effective diameter of the sprocket hole is enlarged and the insertion pins to be inserted into the holes get good fitting thus causing no damage of the sprocket holes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a sprocket hole in a tape carrier.

[Conventional technology]

Conventionally, bumps and ILs formed around the periphery of an LSI chip
The tape carrier for B (inner lead bonding) connection was made by pasting a 35JI+11 thick copper foil with adhesive onto an insulating film made of Kapton, and then forming a lead frame by photo-etching. . Here, as a tape, an insulating film
Because a three-layer structure consisting of adhesive and copper foil was used, the IL
There is a drawback that the insulating film is thermally deformed by the heat from the bonding tool during B, making it unsuitable as a tape carrier for mounting LSI chips that require a large number of bins. A tape carrier consisting of a single layer of copper foil has solved this drawback and has come to be used instead. That is, the structure was as shown in FIG. 3(a). The thickness of a tape carrier made of one layer of copper foil is generally 70 μm from the viewpoint of heat dissipation characteristics and mechanical strength.

However, structures requiring a very large number of bins and a narrow lead pitch are difficult to form by etching from one side due to restrictions on the amount of side etching.

Therefore, sprocket holes and device holes were connected by etching from both sides of the tape.

[Problem to be solved by the invention]

In the conventional tape carrier made of a single piece of copper foil that requires a very large number of pins and a narrow lead pitch, as shown in FIG. 3(b),
As shown in (c), since exposure is performed separately on the front and back sides of the tape, there is a drawback that, for example, a positional shift occurs between the sprocket hole 11 on the front side and the sprocket hole 1j on the back side. .

Therefore, during tape carrier production, tape transport and ILB
The sprocket did not fit well with the insertion bin inserted into the sprocket hole used when cutting and forming the lead frame to perform 0LE (Outer Lead Bonding) and to align the LSI chip with the tape carrier. There is a problem in that the holes are damaged and as a result, the yield in manufacturing and assembling the tape carrier is not increased and costs are increased.

The present invention provides a tape carrier for mounting an integrated circuit, which prevents the sprocket holes from being misaligned between the front and back surfaces as described above.

[Means to solve the problem]

The tape carrier of the present invention includes a first opening portion in which at least the sprocket hole has a first size from one side of the carrier tape and has a depth equal to or more than half the thickness of the tape metal layer; From the other side of the tape at the same position as the first hole, a depth having a second size larger than the first size and having a thickness of at least half the thickness of the metal layer and smaller than the thickness of the metal layer is formed. and a second aperture having a diameter, and the region where the tenth aperture is formed is completely located within the region where the second aperture is formed.

That is, the tape carrier of the present invention has sprocket holes of different sizes on the front and back sides of the tape. Therefore, the effective diameter of the sprocket hole becomes large, and the insertion pin inserted into the hole is well fitted, and the sprocket hole is not damaged.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1(a) is a plan view showing the first embodiment of the present invention, FIG. 1(b) is a cross-sectional view taken along line A-A in FIG. 1(a), and FIG. 1(c) is a plan view showing the first embodiment of the present invention. It is a sectional view taken along the line BB in FIG. 1(a).

The method for forming the tape carrier of the present invention is shown below.
After applying photoresist to both sides of a single-layer copper foil tape with a thickness of m, the sprocket hole 1b and device hole 2 on one side (back side) are exposed and developed, and then etched with a well-known etching solution such as cupric chloride. After etching approximately 1/2 of the tape thickness (so-called half etching), the etched portion is masked, and on the opposite side (surface) of the tape, the block hole 1a, device hole 2, and lead frame 3 are etched. is formed by the photoetching method in the same manner as above. In this way, the sprocket hole 1a on the front surface and the sprocket hole ib on the back surface can penetrate. The sprocket hole lb formed on the back side corresponds to the maximum positional deviation of the photomask during exposure (approximately ±150 μm)
Finally, the tape carrier according to the present invention can be realized by peeling off the photoresist and performing well-known gold plating or tin plating.

In this example, the sprocket hole lb formed on the back side
Although the sprocket hole 1a is formed larger than the sprocket hole 1a formed on the surface, it can also be realized by forming the sprocket hole 1a with the opposite size.

FIGS. 2(a) to 2(c) are plan views of Embodiment 2 of the present invention.

This embodiment shows an embodiment in which the sprocket hole shape is other than square. Fig. 2(a) is a circular embodiment, Fig. 2(b) is an elongated embodiment, and Fig. 2(b) is an elongated embodiment.
Figure (c) shows another embodiment with a hexagonal shape. Figure 2 (a
) By making it circular, it is possible to improve the fit with the insertion pin compared to the actual position 1. That is, by tapering the insertion pin into a conical shape, it is possible to absorb errors in finished dimensions of the sprocket hole and achieve stable fitting.

Although FIGS. 2(a) to 2(c) each show a configuration in which each row has the same shape, one row may be combined with another shape.

〔Effect of the invention〕

As explained above, the present invention improves the fitting with the insertion pin by having sprocket holes of different sizes on the front and back sides of the tape, making it possible to prevent damage to the sprocket holes, and making it possible to improve the fit of the tape carrier. This has the effect of reducing costs because the production yield can be improved. Furthermore, since the positioning accuracy during ILB and OLB can be improved, the assembly yield can be measured.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view showing the whole tape carrier of the first embodiment according to the present invention, FIG. 1(b) is a sectional view taken along line A-A in FIG. Figure (c) is Figure 1 (a)
FIG. 2(a) is a sectional view taken along line B-B of FIG.
FIG. 2 is a plan view showing the entire tape carrier of the embodiment of FIG.
Figures (b) and 2 (c) show the 3rd stage with a sprocket hole shape. 3(a) is a plan view showing the entire tape carrier; FIG. 3(b) is a plan view showing misalignment of the sprocket hole; FIG.
c) is a sectional view taken along line CC in FIG. 3(b). la, lb, lc, ld, Ie, If, Ig. 1h...Sprocket hole, 2...
Device hole, 3...Lead frame.

Claims (1)

[Claims] In a tape carrier consisting of a single metal layer and having a device hole, a lead frame, and a sprocket hole,
a first opening portion in which at least the sprocket hole has a first size and a depth equal to or more than half the thickness of the metal layer from one side of the tape; from the other surface of the tape at the same position as the metal layer, the second size is larger than the first size, and the depth is at least half the thickness of the metal layer and smaller than the thickness of the metal layer. a carrier tape for integrated circuit mounting, characterized in that the region in which the first aperture is formed is completely located within the region in which the second aperture is formed; .